Laparoscopic, or “keyhole” surgery involves a surgeon performing a surgical procedure on a patient using instruments that are inserted into the body, but which are manipulated using hand/robotic controls located externally of the patient. The surgeon usually sees what is happening by using an endoscope which is inserted at or near the operation site and in order to gain access to the operation site and to provide space for the instruments, a cavity is usually opened up within the patient's body by inflation using a suitably inert gas, such as CO2.
Many laparoscopic procedures involve the use of thermal cutting instruments, such as lasers and diathermy devices, which can cut and cauterise tissues by ablation, heating, freezing and the like. In certain situations, the surgeon's view can be become obscured by smoke, vapours or other aerosols and it is therefore often necessary to provide means for extracting the smoke, vapours or aerosols from the operation site. The extraction of smoke, vapours and aerosols can be achieved in a number of ways, such as by over-pressurising the cavity and providing a gas bleed tube fitted with a filter.